Citation metrics influence academic reputation and career trajectories. Recent works have highlighted flaws in citation practices in the neurosciences, such as the under-citation of women. However, self-citation rates—or how much authors cite themselves—have not yet been comprehensively investigated in the neurosciences. This work characterizes self-citation rates in basic, translational, and clinical neuroscience literature by collating 157,001 articles from 63 journals between the years 2000-2020. In analyzing over eight million citations, we demonstrate four key findings: 1) self-citation rates over the years are constant for the Last Authors but decreasing for the First Authors, 2) self-citation rate is strongly correlated with years of academic experience, 3) authors from particular countries cite themselves much more than other countries, and 4) early-career men cite themselves 41% more than early-career women. As it is essential for authors to be aware of their self-citation practices, we developed a tool to calculate self-citation rates: https://github.com/mattrosenblatt7/self_citation. Our characterization of self-citation practices represents an initial step towards improving equity in citations and, ultimately, neuroscience research.